Comparative Study Of D And F Blocks Elements Bsc Exam (Page 3 of 3) in pdf

Comparative Study Of D And F Blocks Elements Bsc Exam Page 3

3. (a) Describe the preparation, properties ,uses and the structure of nitrosonium pentaquo

iron (I) sulphate.

[7 marks]

(b) Account for the following observations;

(i) Lanthanide and actinide metal ions show sharp almost line like bands in their

electronic spectra

(ii) Ce

shows exceptionally strong absorptions in the UV region

(iii) Transition metals readily form alloys with each other

(iv) Low valent transition metal ions readily form complexes with

π-acid ligands

(iv) ν

in carbonyl complexes is different from that of CO molecule

(v) Lanthanides and actinides generally have high boiling points compared to the

main block elements

(vi) Co-ordination number less than 7 is rare in complexes of d-block elements

[12 marks]

4. (a) Using molecular orbital theory show that CO is π-acid ligand.

[4 marks]

(b) Illustrating with an example each, give three methods of preparing a metal carbonyl

[6 marks]

is tetrahedral and diamagnetic. Describe the bonding in this complex

using valence bond theory.

[Atomic number Ni=28]

[4 marks]

(ii) Calculate the effective atomic number of Ni in the complex and comment

briefly on your answer

[2 marks]

(d) Infrared and x-ray studies of Co

(CO)

, shows that the compound does not have

a bridging carbonyl and the metal ions are in an octahedral environment. Describe

the bonding in the compound using valence bond theory.

[Atomic number; Co =27]

[4 marks]

(e) Differentiate between organometallic compound and coordination

compound

[1 mark]

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